1. Prince Henry’s Institute of Medical Research (D.M.R., H.G.B.), Clayton, Victoria 3168, Australia
2. Department of Obstetrics and Gynaecology (G.E.H., I.S.F.), Queen Elizabeth II Research Institute for Mothers and Infants (DO2), University of Sydney, New South Wales 2006, Australia
3. Monash Institute of Health Services Research (D.J.), Monash University, Clayton, Victoria 3168, Australia
4. Quintiles Inc. (C.L.H.), Research Triangle Park, North Carolina 27709